Such a parking lock has been disclosed by DE 36 36 978 A1. The output of this transmission is directly connected to a parking lock gear, so that, when in parking mode, a locking member in the form of a parking lever, upon option, can be lockingly brought into engagement with toothing of the parking lock gear. A push-rod, which is indirectly connected with a selection lever of the transmission, carries a conical cam, which, in the parking position of the said selection lever, brings the locking member into such a position, that the parking lock brake gear is in the locked condition. Thereby, by this establishment of the parking position and with even an unfavorable relative position of the park locking gear, an engagement can securely be made, if the said cam is spring loaded and slidably placed on the insertion rod. To this end, the said push-rod carries a molded on connection, upon which a compression spring can anchor, which then exerts force on the said cam. So that, in a case of extreme vibration, which can act upon this known transmission, the lock member, which is in the driving mode, can undesirably contactingly engage with the parking lock gear, there is provided on the insertion rod a braking member spring in the form of a leaf-spring. This spring is so designed, that in a driving gear stage, it exerts its resilient force on the lock member, and works against an engagement of the lock member in the parking lock gear.
In cases of increased demands, in regard to resistance of a parking lock mechanism to vibratory disturbance, in order hold the locking lever free from engagement in the parking lock gear, the force of the leaf spring must be made greater. Due to substantial friction caused by the spring, an increased expenditure of force is created between the leaf spring and the locking lever. As a result, an axial sliding of the cam is initiated, and thus an increased expenditure of force appears at the selector lever. Such increased demands can, for example, occur with motor vehicles equipped with such parking locks, if these are driven at excessive speeds over unlevel obstructions or in off-the-road courses.
Giving consideration to this background, thus the purpose of the invention is to create a parking lock for an automatic transmission of such a nature, that in the driving mode, even at extreme accelerations acting upon the transmission, contact between the locking lever and the parking lock gear is avoided.